The ink in accordance with this invention is characterized by being self-supporting and no prior art or the like is known in which a thermal ink is self-supporting. The standard transfer ribbon having thermoplastic ink comprises a supporting substrate upon which the thermoplastic ink is formed. The substrate is a part of the ribbon and remains with the ink to provide necessary physical characteristics for ribbon movement during printing. Materials substantially identical to those which might be used to formulate a thermoplastic ink in accordance with this invention are used with the prior transfer mediums. No suggestion is known indicating that such formulations are self-supporting.
Illustrative teachings of such prior art formulations all of which, expressly or by implication, are on a supporting substrate are as follows: U.S. Pat. No. 4,308,318 to Weiche, which teaches a formulation employing a polyamide. U.S. Pat. No. 4,384,797 filed Aug. 13, 1981, by C. W. Anderson et al (and assigned to the assignee of this application), which teaches a blend of ethylene vinyl acetate and ethyl methacrylate. IBM Technical Disclosure Bulletin articles as follows: "Thermal Transfer Ink" by G. A. Waldrip, Vol. 24, No. 7B, December 1981, at p. 3949, which teaches a polyketone and polyamide blend; "Resistive Ribbon Ink Layers" by W. Crooks et al, Vol. 22, No. 2, July 1979, at p. 782, which teaches a butyl half ester of a copolymer of methyl vinyl ether and maleic and anhydride; "Layer Forming Inks for Lift-off Correction" by C. W. Anderson, et al, Vol. 24, No. 4, September 1981, at p. 1790, which discloses a mixture of ethylene vinyl acetate copolymer with polyethylene glycol and polyoleate and polyglycol esters and fatty acids and ethylene vinyl acetate copolymer, as well as other mixtures including mixtures including polyamide resin; and "Tackified Correctable Inks" by C. W. Anderson et al, Vol. 23, No. 12, May 1981, at p. 5461, which teaches an ethylene vinyl acetate copolymer based ink with methyl ester of natural rosin. Other such prior art might be mentioned, but it is considered essentially cumulative to the foregoing, none of which is considered directly significant since it does not teach a self-supporting lamination.